1. Field of the Invention
The invention relates in general to elevator systems, and more specifically to monitoring systems for remotely monitoring and exercising elevator installations. 2. Description of the Prior Art
The elevator cars of a bank of elevator cars in medium and high speed elevator systems are usually controlled by a system processor which directs the operation of a plurality of elevator cars to answer calls for elevator service according to a predetermined strategy. For many years, the system processor was of the hardwired relay type, but with the development of reliable solid state control devices, the relay system processors are being replaced by solid state logic control devices, as well as by programmable type dispatchers which include a digital computer and software package.
Regardless of the type of system processor, the individual car performance as well as the overall system operation should be periodically checked as part of a preventive maintenance program. Maintenance personnel should periodically check the individual cars to insure that they level to within the prescribed limits prior to full door openings, and that doors operate properly, opening and closing at the proper speed and remaining open for the desired non-interference time. Other important items should also be checked, such as whether or not the car properly becomes available for assignment by the system processor when the elevator car is not busy. Also, it is important to know whether or not the elevator car being checked has been intermittently going out of service.
In addition to checking each elevator car, maintenance personnel should also check system operation, to insure that all of the features of the strategy are functional. Stop watch timing is now used to check average waiting time for hall call service, floor-to-floor time, and average round trip time for a car leaving the main floor. The frequency of by-passing of the cars due to full-loads should also be determined.
Machine room checks of the drive motors should also be made, checking such items as motor bearing vibration and temperature, armature current, and armature brush wear.
It will be realized that intermittent faults will not easily be observed by the maintenance personnel, and that it is very difficult for them to conduct an accurate traffic study to determine if the system processor is operating properly and providing all of the functions that it was designed for. It is even more difficult to reduce stop watch timing data to meaningful data, such as mean waiting and round trip times.
Since it is highly desirable that actual out of service time for an elevator car, or a bank of elevator cars, be kept to an absolute minimum, an elevator trouble reporting system has been disclosed in U.S. Pat. 3,209,324 which automatically reports a fault or safety device operation to a selected central office location. The fault or safety device operates a trouble reporting device which selects one of a plurality of pre-recorded tape messages to transmit to the central location. This arrangement facilitates prompt service for an actual fault or safety device operation, and thus reduces out of service time by promptly reporting the type of fault or safety device which operated.